Although environmental management dates back to the 1930s, there has never been legislation in Lesotho to make EIA mandatory. Various environmental policies such as the National Environmental Plan and the Agenda 21 Action Plan have called for EIA in Lesotho. Moreover, experience of the ad hoc EIA of the Highlands Water project teaches that EIA should be a normal part of Lesotho's development planning process. The challenge of institutionalising EIA in Lesotho will depend on factors such as physical size of projectrs, financial magnitude, availability of local expertise, shared resources within the framework of regional cooperation, and the national institutional framework. All these can be strengthened through use of general principles of prevention, polluter-pays, and cooperation.